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Steel SNCM630-A vs SNCM630-CD

Steel · SNCM630 temper comparison

SNCM630-A and SNCM630-CD are two conditions of the same steel grade, SNCM630: A (solution annealed) versus CD (cold drawn). The chemistry is identical, so every difference below comes from the condition. SNCM630-CD is the stronger of the two: yield strength 800 MPa (116 ksi) against 640 MPa (92.8 ksi) for SNCM630-A, about 25% more; tensile strength follows at 950 MPa (138 ksi) vs 850 MPa (123 ksi). In exchange, SNCM630-A is the more ductile: elongation 20% versus 12% for SNCM630-CD, and SNCM630-CD is harder (280 HB vs 250 HB). SNCM630-A runs hotter in service (400°C vs 350°C continuous) and SNCM630-CD conducts heat better (38 W/m·K vs 34 W/m·K).

SNCM630-AChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

SNCM630-CDChoose it when strength drives the design.

SNCM630-A vs SNCM630-CD: properties

SNCM630-ASNCM630-CD

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

850 MPa123 ksi
950 MPa138 ksi

Yield Strength (0.2% offset)

640 MPa92.8 ksi
800 MPa116 ksi

Elongation at Break

20%
12%

Reduction in Area

55%
35%

Compressive Strength

1,020 MPa148 ksi
820 MPa119 ksi

Shear Strength

690 MPa100 ksi
570 MPa82.7 ksi

Fatigue Strength (Endurance Limit)

400 MPa58 ksi
420 MPa60.9 ksi

Fracture Toughness (K_IC)

85 MPa·√m77.4 ksi·√in
65 MPa·√m59.2 ksi·√in

Charpy V-Notch Impact (RT)

55 J40.6 ft·lbf
25 J18.4 ft·lbf

Hardness, Brinell

250 HB
280 HB

Hardness, Rockwell C

24 HRC
28 HRC

Hardness, Vickers

340 HV
295 HV

Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,490°C2,714 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

34 W/m·K19.6 BTU/hr·ft·°F
38 W/m·K22 BTU/hr·ft·°F

Max Service Temperature (continuous)

400°C752 °F
350°C662 °F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -60°C-76 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

5.5 % IACS
5.7 % IACS

Electrical Resistivity

3.1×10⁻⁷ Ω·m12.2 µΩ·in
3×10⁻⁷ Ω·m11.8 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

14 / 100
13 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

52 / 100
48 / 100

Machinability Rating (AISI 1212 = 100 %)

58%
55%

Weldability

38 / 100
30 / 100

Formability (cold)

38 / 100
20 / 100

Same in both: Castability 45 / 100 · Brazeability / Solderability 50 / 100 · Polishability 72 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 34 MJ/kg14,617 BTU/lb · Embodied Carbon (primary production) 2.5 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 30%

Strength versus weight

Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleSNCM630

SNCM630-A vs SNCM630-CD — frequently asked

Is SNCM630-CD stronger than SNCM630-A?

Yes. SNCM630-CD has a typical yield strength of 800 MPa (116 ksi) against 640 MPa (92.8 ksi) for SNCM630-A — about 25% more. Tensile strength is 950 MPa (138 ksi) vs 850 MPa (123 ksi).

Which condition does FabDigit quote by default, A or CD?

QT-H is the default SNCM630 condition in the FabDigit quote flow (neither A nor CD). The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.

Which welds better, SNCM630-A or SNCM630-CD?

SNCM630-A. Its weldability rates fair (38/100) against poor (30/100) for SNCM630-CD.

Ready to make it?

Upload a CAD file and FabDigit prices the part in SNCM630-A and SNCM630-CD side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.